TRANSIENT LOSS OF SERUM PROTECTIVE ACTIVITY FOLLOWING SHORT-TERM STRESS - A POSSIBLE BIOCHEMICAL LINK BETWEEN STRESS AND ATHEROSCLEROSIS

Very low density lipoproteins (VLDL) are toxic to aortic endothelial c ells in vitro, and toxicity preventing activity (TxPA) inhibits this t oxic effect of VLDL. Stress, an established arteriosclerosis risk fact or, was examined for its effect on TxPA and on the ability of serum to protect endothelial cells from in vitro injury by VLDL. A standardize d mirror tracing task with noise was administered to four healthy subj ects. Blood samples were obtained at 0, 30, (stressor) 35, 50 and 80 m in. Cortisol and non-esterified fatty acids increased during the stres s period. TxPA significantly decreased following the stressor and had recovered by 80 min. When the ratio of non-TxPA/TxPA rose above 2, ser um was no longer able to protect the cells from VLDL injury. If endoth elial cells in vivo respond similarly to the endothelial cells in cult ure, the effect of stress on atherosclerosis may be mediated through t hese transient decreases in TxPA.